The purpose of an Oxford magnet system consisting of a sweeping, wide bore superconducting magnet (0-7 Telsa) with variable temperature insert (4-500 K) is proposed. This magnet system is a self-contained, independently operable instrument that will that will be used to expand significantly the capabilities of the VHF (Very High Frequency) 95 GHz (W-band) EPR spectrometer, presently in operation at the Illinois EPR Research Center. With this magnet system, the full potential of high frequency EPR spectroscopy can be exploited by providing sufficient space for the full range of temperature control, access of light, use of a perfusion system and by expanding the non-superconducting sweeping field from 200 to 1000 Gauss. In particular, this magnet system will enable the investigators studying high-spin metallo-proteins and related high-spin systems to use VHF EPR spectroscopy to characterize the metal sites through direct observation of zero-rield split energy levels and increased g-value resolution and addition benefits as described in the proposals. The instrument proposed here will meet the research needs of six main investigators in chemistry, physics, biophysics, biochemistry and medicine addressing a wide variety of problems. These research groups already have expertise in EPR instrumentation and theory, and they will share in the support of the equipment. The maintenance will be taken care of through a cooperative arrangement with the Illinois EPR Research Center (IERC), an NIH-supported research resource whose staff has extensive experience in EPR instrumentation and application. The proposed equipment will greatly improve the spectroscopic capabilities for investigators conducting biomolecular/biomedical research at the University of Illinois.